Add drupal role support to CiviCRM groups and Membership types

Static Groups:

Add/Delete all members of group X => drupal role Y

Membership:

Add/Delete contact with is_current_member of membership type X => drupal role Y

We need to create an admin screen to map groups / membership types to drupal roles. Ideally this should be done with hooks and takes place immediately. We should also hook this to UpdateMembershipRecord to ensure we delete roles for non current members